Biphasic Motion Research Articles

BIPHASIC MOTION OF THE MEDIAN NERVE IN THE NORMAL ASIAN POPULATION

The biomechanical interaction between the median nerve and the flexor tendons is an important consideration in Carpal tunnel syndrome (CTS). We aim to quantify the displacement and compressive deformation pattern of the median nerve in various stages of finger flexion in the normal population at the inlet of the carpal tunnel. Transverse ultrasounds images were taken at the carpal tunnel inlet during full-extension, mid-flexion and full flexion. The displacement, distance, Feret's diameter, and perimeter of the median nerve were calculated and compared between each position. Biphasic median nerve motion was observed, with a displacement of 2.84 ± 3.49 mm in the ulnar direction from full-extension to mid-flexion (Phase I) and a further 0.93 ± 3.04 mm from mid-flexion to full flexion (Phase II). Of 49 hands, 37 (75.5%) exhibited ulnar displacement in Phase I while 12 (24.5%) exhibited radial displacement. Feret's diameter (5.95 ± 1.08 mm) and perimeter (13.28 ± 2.09) of the median nerve were greatest in the mid-flexed position. In a healthy Asian population, the median nerve has a biphasic motion during finger flexion, with maximal deformation in the mid-flexed position.

A model of oculomotor tracking suggests a biphasic motion response

A model of oculomotor tracking suggests a biphasic motion response

Doppler tissue imaging improves assessment of abnormal interventricular septal and posterior wall motion in constrictive pericarditis

We hypothesized that Doppler tissue imaging in the short axis would provide enhanced quantitative information for differentiating the pattern and extent of abnormal septal and posterior wall motion in constrictive pericarditis (CP). Using quantitative pulsed wave and color M-mode Doppler tissue imaging, we quantified the pattern of abnormal septal and posterior wall motion and studied its incremental advantage over conventional M-mode and 2-dimensional echocardiography in 40 patients with surgically proven CP. The pattern and extent of abnormalities were compared with 35 age- and sex-matched control subjects and 20 patients with abnormal septal motion of other causes. In 33 patients (82.5%) with CP, the interventricular septum showed high-velocity (>7 cm/s) early diastolic biphasic motion with or without multiple recoil waves (polyphasic diastolic septal fluttering). In the posterior wall, the early diastolic wave was normal but the late diastolic wave was reduced in 24 patients (60%) and absent in 7 (17.5%). In comparison, M-mode and 2-dimensional echocardiography identified abnormal septal or posterior wall motion in 24 patients (60%) ( P = .003). The pattern of abnormal septal motion in CP could be differentiated from abnormal septal motion of other causes in 16 patients (80%). The overall sensitivity and specificity of high-velocity polyphasic septal flutter for differentiating CP from control cases and other diseases was 82.5% and 92.7%, respectively. In CP, Doppler tissue imaging in the short axis provides unique diagnostic information and reliably differentiates CP from control cases and most other causes of abnormal septal motion.

Action of metallic ions on the precocious development by rabbit sperm of motion patterns that are characteristic of hyperactivated motility.

An earlier study demonstrated that rabbit sperm incubated for 16 hr under capacitation conditions acquire motility patterns identical to those seen in rabbit sperm capacitated in vivo. We now show that similar motion patterns develop after 0.5 hr incubation in a Tris-buffered medium, medium M. Development and decline of the motion patterns occurred in three phases each recognized by the character of the biphasic motion patterns. Hyperactivated sperm were objectively identified and quantified by a previously developed computer-directed model. The percentage of motile sperm that acquired hyperactivated motility and the period they remained in this state varied among sperm from different rabbits. The decline in hyperactivated motility was paralleled by a decrease in the average sperm curvilinear velocity (VCL) and average amplitude of lateral head displacement (AALH), but was not accompanied by a concomitant decrease in percentage of motile sperm. Pb2+ and Cd2+, at concentrations that did not inhibit motility, prevented development of hyperactivated motility. Inhibition of hyperactivated motility by Pb2+ was time- and concentration-dependent; the average percentage of hyperactivated sperm decreased from approximately 30% to < 5% (n = 5) in 1 hr at a Pb2+ concentration of 25 microM. Cd2+ inhibition of hyperactivation was dependent only on concentration of the cation. At a concentration of 100 microM, the decrease in the percent of hyperactivated sperm was approximately 50% (n = 3). Hg2+, Zn2+, and Cr6+ at sublethal concentrations had no effect on hyperactivated motility development. These results suggest that Pb2+ and Cd2+, by virtue of their ability to prevent the wide curvature flagella beating that is characteristic of hyperactivation, can compromise fertilization at concentrations that do not inhibit sperm motility and act as a reproductive toxicant at a level other than spermatogenesis.

Cineventriculographic analysis of the ventricular septal motion during stimulation of various pacemaker sites.

By means of cineventriculography, contraction pattern of the ventricular septum was studied during electrical stimulation of the right atrium (RA), outflow tract (RVO) and apex (RVA) of the right ventricle and apex (LVA) and lateral wall (LVL) of the left ventricle. RA pacing produced a monophasic shortening of the septal hemiaxes after initial lengthening for about 40 msec from R wave of ECG. In contrast, ventricular stimulation near the septum (i.e. RVO, RVA and LVA) resulted in a biphasic and decreased contraction of the septal wall, in which an early preejection shortening was followed by a brief lengthening and second shortening. LVL pacing showed a monophasic and increased contraction of the septal wall. The biphasic motion of the septal wall was likely to be related to the abnormal mechanical contraction caused by the abnormal conduction sequence of ventricular depolarization. On the other hand, the lateral wall demonstrated a biphasic and decreased contraction during LVL pacing, and a monophasic and increased contraction during RVO, RVA and LVA pacing. Thus, the biphasic and diminished contraction at the site of electrical stimulation was compensated by the monophasic and forceful contraction of the contralateral wall. It is considered that the ventricular septum plays an important functional role in regulation of cardiac performance.